Illlumination device and liquid crystal display device

ABSTRACT

According to one embodiment, an illumination device includes a light source disposed along a first direction, a light guide plate including a first end and a second end, the second end being positioned to be opposite to the first end in a second direction which crosses the first direction, a frame disposed along the second end and including an inner surface and an upper surface, and an adhesion member disposed on at least the upper surface of the frame, wherein the light source is disposed at the first end along the first direction, at least the inner surface of the frame is a light absorbing surface, and the adhesion member is light transmissive.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of application Ser. No. 15/494,807filed Apr. 24, 2017, which is based upon and claims the benefit ofpriority from Japanese Patent Application No. 2016-089787, filed Apr.27, 2016, the entire contents of which are incorporated herein byreference.

FIELD

Embodiments described herein relate generally to an illumination deviceand a liquid crystal display device.

BACKGROUND

Liquid crystal display devices are used in various technical fields.Liquid crystal display devices include a display panel, a backlight unitas an illumination device, and the like. A backlight unit includes, forexample, a light source, light guide plate, frame formed of a whiteresin, black adhesive sheet (light shielding doubled-sided tape), andthe like.

Recently, display devices are required to have a thinner bezel structureand a bezel area where a backlight unit and a display panel are adheredis made significantly small. This makes it difficult to perform finetreatment of a light shielding double-sided tape, to precisely adherethe light shielding double-sided tape to the frame, and to preciselyattach the backlight unit and the display panel. As a result, if thereis a difficulty in treatment and adhesion of a light shieldingdouble-sided tape, the light shielding double-sided tape may berecognized by a user or may block light passing through pixels, and thedisplay quality may be deteriorated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the structure of a display device of anembodiment.

FIG. 2 shows the structure of the display device of the embodiment andan equivalent circuit thereof.

FIG. 3 shows an equivalent circuit of a pixel of FIG. 2.

FIG. 4 is a cross-sectional view of the display panel.

FIG. 5 is a cross-sectional view of the display device including ends ofthe light guide plate.

FIG. 6 shows a relationship between the adhesion member of theembodiment and a viewing angle of a user.

FIG. 7 shows a variation 1 of the adhesion member of the embodiment.

FIG. 8 shows a variation 2 of the adhesion member of the embodiment.

FIG. 9 is a perspective view showing a variation 3 of the display deviceof the embodiment.

FIG. 10 is a cross-sectional view of the display device of FIG. 9.

DETAILED DESCRIPTION

In general, according to one embodiment, an illumination devicecomprising: a light source disposed along a first direction; a lightguide plate including a first end and a second end, the second end beingpositioned to be opposite to the first end in a second direction whichcrosses the first direction; a frame disposed along the second end andincluding an inner surface and an upper surface; and an adhesion memberdisposed on at least the upper surface of the frame, wherein the lightsource is disposed at the first end along the first direction, at leastthe inner surface of the frame is a light absorbing surface, and theadhesion member is light transmissive.

According to an embodiment, a liquid crystal display device comprising:a display panel including: a first substrate, a second substrate opposedto the first substrate, a liquid crystal layer held between the firstsubstrate and the second substrate, and a polarizer adhered to the firstsubstrate; and an illumination device which illuminates the displaypanel, wherein the illumination device comprises: a light sourcedisposed along a first direction; a light guide plate including a firstend and a second end, the second end being positioned to be opposite tothe first end in a second direction which crosses the first direction; aframe disposed along the second end and including an inner surface andan upper surface; and an adhesion member disposed between the displaypanel and the frame and adheres the display panel and the frame, whereinthe light source is disposed at the first end along the first direction,at least the inner surface of the frame is a light absorbing surface,and the adhesion member is light transmissive.

According to an embodiment, a liquid crystal display device comprising:a display panel including: a first substrate, a second substrate opposedto the first substrate, a liquid crystal layer held between the firstsubstrate and the second substrate, and a light shielding layer disposedin a non-display area around a display area; and an illumination devicewhich illuminates the display panel, wherein the illumination devicecomprises: a light source disposed along a first direction; a lightguide plate including a first end and a second end, the second end beingpositioned to be opposite to the first end in a second direction whichcrosses the first direction; a frame disposed along the second end; andan adhesion member disposed between the display panel and the frame andadheres the display panel and the frame, wherein the light source isdisposed at the first end along the first direction, the light shieldinglayer includes an end positioned in a boundary between the display areaand the non-display area, and a light shielding member is not disposed,in a plane defined by the second direction and a third direction whichcrosses the first direction and the second direction, on a line passingthe end of the light shielding layer and the frame, wherein the line isat an angle of 45 degrees with respect to the normal of the displaypanel.

Embodiments will be described hereinafter with reference to theaccompanying drawings. The disclosure is merely an example, and properchanges within the spirit of the invention, which are easily conceivableby a skilled person, are included in the scope of the invention as amatter of course. In addition, in some cases, in order to make thedescription clearer, the widths, thicknesses, shapes, etc. of therespective parts are schematically illustrated in the drawings, comparedto the actual modes. The schematic illustration is merely an example,and adds no restrictions to the interpretation of the invention. In thespecification and drawings, the structural elements having functions,which are identical or similar to the functions of the structuralelements described in connection with preceding drawings, are denoted bylike reference numerals, and an overlapping detailed description will beomitted arbitrarily.

Initially, a display device of the present embodiment will be explained.In the present embodiment, a display device DSP is a liquid crystaldisplay device. The liquid crystal display device is used in variousdevices such as smartphones, tablets, feature phones, personalcomputers, televisions, in-car devices, and gaming devices.

FIG. 1 is a perspective view showing the structure of the display deviceDSP of the present embodiment. In the figure, a first direction X,second direction Y, and third direction Z are orthogonal to each other;however, they may cross at angles other than 90 degrees. An X-Y planedefined by the first direction X and second direction Y are parallel tothe main surface of the display device DSP and the third direction Zcorresponds to a thickness direction of the display device DSP.

The display device DSP includes a display panel PNL, driver IC chip 2which drives the display panel PNL, flexible printed circuit FPC,illumination device (backlight unit) BL which illuminates the displaypanel PNL, and cover CV.

The display panel PNL is a liquid crystal panel and includes a firstsubstrate SUB1, a second substrate SUB2 opposed to the first substrateSUB1, and a liquid crystal layer held between the first substrate SUB1and the second substrate SUB2. Note that the liquid crystal layer isextremely thin as compared to the thickness of the display panel PNL andis disposed inside the sealant which adheres the first substrate SUB1and the second substrate SUB2, and thus, its depiction is omitted.Furthermore, the display panel PNL includes a display area DA in whichan image is displayed, and a frame-like non display area NDA surroundingthe display area DA. A plurality of pixels PX are disposed in a matrixin the display area DA. The drive IC chip 2 and the flexible printedcircuit FPC are mounted on the first substrate SUB1 in the non-displayarea NDA.

The illumination device BL is disposed in one outer surface PNLa side ofthe display panel PNL (or a side opposed to the first substrate SUB1 ofthe display panel PNL). The illumination device BL includes, in theexample depicted, an adhesion member AD1, sheet member OS, light guideplate LG, light unit LU, frame FR, and reflective sheet RS.

The sheet member OS is light transmissive and is disposed in the outersurface PNLa side. In the example depicted, the illumination device BLincludes, as the sheet member OS, a prism sheet OSA or a diffusion sheetOSB, and may include a sheet of any different function in addition tothe two sheets as depicted. In the example depicted, the sheet member OSis formed in a rectangular shape and is opposed to the display area DA.Note that the sheet member OS is not limited to a rectangular shape andmay be a quadrangle two adjacent sides of which are not 90 degrees.

The light guide plate LG is formed as a flat plate and is opposed to thesheet member OS. The light guide plate LG includes a main surface LGAopposed to the sheet member OS, main surface LGB opposite to the mainsurface LGA, and ends LGe1, LGe2, and LGe3 which are side surfacesconnecting the main surface LGa and the main surface LGb. The ends LGe1and LGe2 extend in the first direction X and the end LGe3 extends in thesecond direction Y. The end LGe1 is, in the display panel PNL, opposedto the area where the driver IC chip 2 and the flexible printed circuitFPC are mounted in the third direction Z. The end LGe2 is disposed inthe opposite side of the end LGe1 in the second direction Y.

The light unit LU includes a plurality of light sources LS arranged inthe end LGe1 of the light guide plate LG in the first direction X, aflexible printed circuit LFPC in which the light sources LS are mounted,and the like.

The frame FR is disposed in the outer surface PNLa side. The frame FR isprovided with at least the end LGe2 of the light guide plate LG. Thatis, the frame FR is disposed, in the end of the light guide plate LG, inthe opposite side of the end LGe1 where the light sources LS aredisposed. Or, the frame FR may be provided in a rectangular frame shapesurrounding the light guide plate LG and the sheet member OS, or may beprovided with the three sides surrounding the light guide plate LG andthe sheet member OS excluding the end LGe1 where the light sources LSare disposed. In the example depicted, the frame FR is formed in arectangular frame shape surrounding the light guide plate LG and thesheet member OS and includes a rectangular opening OP in the areaopposed to the display area DA.

The reflective sheet RS is light reflective and is disposed in the lightguide plate LG in its side opposed to the main surface LGB. Althoughthis is not explained in detail, the reflective sheet RS is adhered tothe frame FR. The reflective sheet RS and the frame FR as above functionas a container to accommodate the light guide plate LG, sheet member OS,and light unit LU.

The adhesion member AD1 is formed in a rectangular shape and is disposedbetween the display panel PNL and the frame FR. As will be explainedlater, the adhesion member AD1 adheres the display panel PNL and theframe FR in a position opposed to the non-display area NDA of thedisplay panel PNL. Thus, the illumination device BL and the displaypanel PNL are formed integrally.

The cover CV is disposed in the other outer surface PNLb side of thedisplay panel (or, in the side opposite to the second substrate SUB2 ofthe display panel PNL). The cover CV is formed of, for example, glass.In that case, the cover CV will be referred to as a cover glass. Or, thecover CV may be formed of a light transmissive material such as a resin.

Note that the display device DSP structured as above corresponds to atransmissive liquid crystal display device having a transmissive displayfunction which displays an image by selectively passing the lightincident on the display panel PNL in each pixel PX. Note that thedisplay device DSP may be a transflective liquid crystal display devicehaving the transmissive display function and a reflective displayfunction which displays an image by selectively reflecting outer lightor auxiliary light.

FIG. 2 shows the structure of the display device DSP of the presentembodiment. The display panel PNL includes, in the display area DA, scanlines G1 to Gn, signal lines S1 to Sm, and common electrode CE. The scanlines G1 to Gn extend in the first direction X and arranged in thesecond direction Y to be connected to a scan line drive circuit GD inthe non-display area NDA. The signal lines S1 to Sm extend in the seconddirection Y and arranged in the first direction X to be connected to asignal line drive circuit SD in the non-display area NDA. Note that thescan lines G1 to Gn and the signal lines S1 to Sm may not extendlinearly and may be partly bent. The common electrode CE is disposedover the pixels PX and is connected to a common electrode drive circuitCD in the non-display area NDA.

FIG. 3 shows an equivalent circuit of a pixel PX of FIG. 2. The pixel PXincludes a switching element SW, pixel electrode PE, common electrodeCE, liquid crystal layer LQ, and the like. The switching element SWincludes, for example, a thin film transistor (TFT) and is electricallyconnected to a scan line G and a signal line S. The pixel electrode PEis electrically connected to the switching element SW. The pixelelectrode PE of each pixel PX is opposed to the common electrode CE anddrives liquid crystal molecules in the liquid crystal layer LQ using afield produced between the pixel electrode PE and the common electrodeCE. A capacitance CS is formed between, for example, an electrode havingthe potential equivalent to the common electrode and an electrode havingthe potential equivalent to the pixel electrode PE.

FIG. 4 is a cross-sectional view of the display panel PNL. The displaypanel PNL includes the first substrate SUB1, second substrate Sub2,liquid crystal layer LQ, sealant SL, polarizer PL1, polarizer PL2, andthe like.

The first substrate Sub1 includes a first insulating substrate 10 whichis a light transmissive substrate such as a glass substrate or a resinsubstrate. Furthermore, the second substrate SUB2 includes a secondinsulating substrate 20 which is a light transmissive substrate such asa glass substrate or a resin substrate. For example, the first substrateSUB1 includes the above-mentioned scan line G, signal line S, switchingelement SW, pixel electrode PE, and the like. The common electrode CE isdisposed in at least one of the first substrate SUB1 and the secondsubstrate SUB2. The second substrate SUB2 includes a light shieldinglayer BM on the surface of the second insulating substrate 20 which isopposed to the first substrate SUB1. In the present embodiment, thelight shielding layer BM disposed in the non-display area NDA isdepicted alone, and the depiction of the light shielding layer disposedin the display area DA is omitted.

The light shielding layer BM is disposed in the entire area of thenon-display area NDA. An end BMe of the light shielding layer BM ispositioned in the boundary between the display area DA and thenon-display area NDA. The light shielding layer which is not depicted isdisposed in the display area DA to define each pixel and is disposed tobe opposed to the lines such as scan lines, signal lines, and switchingelements on the first substrate SUB1. Furthermore, the sealant SL isdisposed in the non-display area NDA to adhere the first substrate SUB1and the second substrate Sub2. The liquid crystal layer LQ is held inthe area surrounded by the sealant SL between the first substrate SUB1and the second substrate SUB2.

The polarizer PL1 is disposed on the surface of the first substrateopposite to its surface opposed to the second substrate SUB2. Thepolarizer PL1 is adhered to the first substrate SUB1. The polarizer PL2is disposed on the surface of the second substrate SUB2 opposite to itssurface opposed to the first substrate SUB1. The polarizer PL2 isadhered to the second substrate SUB2. Note that the polarizers PL1 andPL2 may include other optical elements such as a retardation plate.Furthermore, in the example depicted, the end PLe1 of the polarizer PL1is disposed outside the end SUB1 e of the first substrate SUB1 and theend PLe2 of the polarizer PL2 is positioned outside the end SUB2 e ofthe second substrate SUB2. Details will be explained later.

FIG. 5 is a cross-sectional view of the display device DSP including theend LGe2 of the light guide plate LG. Note that, in a case where theframe FR is provided with the end LGe3 in the second direction Y, thecross-sectional shape of the display device DSP including the end LGe3will be the same as the cross-sectional shape of FIG. 5, and the detailsthereof will not be explained here.

In the present embodiment, a direction from the non-display area NDA tothe display area DA is defined as inward direction of the display deviceDSP and an opposite direction is defined as outward direction of thedisplay device DSP. Furthermore, a direction from the first substrateSUB1 to the second substrate SUB2 is defined as up or above, and adirection from the second substrate to the first substrate SUB1 isdefined as down or below. Furthermore, a description such as a secondmember above a first member or a second member below a first membermeans that the second member may contact or may be apart from the firstmember. In a case where the second member is apart from the firstmember, a third member may be interposed between the first member andthe second member. A description such as a second member on a firstmember or a second member on the bottom of a first member means that thesecond member contacts the first member.

In the example depicted, the end PL1 e of the polarizer PL1 and the endPL2 e of the polarizer PL2 are disposed outside the end SUB1 e of thefirst substrate SUB1 and the end SUB2 e of the second substrate SUB2.Here, the display panel PNL is an illuminated object of the illuminationdevice BL.

The cover CV is adhered to the polarizer PL2 by an adhesive agent GL.Note that the side of the cover CV opposite to its side opposed to thedisplay panel PNL is a display surface side.

The light guide plate LG is disposed on the reflective sheet RS. Thelight guide plate LG is disposed in the display area DA and extends inthe non-display area NDA. The end LGe2 of the light guide plate LG isdisposed in the non-display area NDA. The sheet member OS is disposed onthe light guide plate LG. The sheet member OS includes a sheet memberOSA and a sheet member OSB, wherein the sheet member OSB overlaps thelight guide plate LG and the sheet member OSA overlaps the sheet memberOSB. The light guide plate LG, sheet member OSA, and sheet member OSBare, for example, layered without being adhered together. The sheetmember OS is disposed in the display area DA and extends in thenon-display area NDA. Furthermore, the sheet member OS extends in thedirection going outside the light guide plate LG. That is, the end OSeof the sheet member OS is disposed in the non-display area NDA and is inthe side apart from the boundary B between the display area DA and thenon-display area NDA than is the end LGe2 of the light guide plate LG.

The frame FR is disposed above the reflective sheet RS. The frame FR isadhered to the reflective sheet RS by an adhesion member AD2. The frameFR includes an inner surface IS and an upper surface US surrounding thelight guide plate LG and the sheet member OS. The inner surface IS andthe upper surface US are arranged along the second end LGe2.

The inner surface IS includes, for example, a first surface IS1, secondsurface IS2, and third surface IS3. The first surface IS1 is opposed tothe light guide plate LG in the second direction Y. The second surfaceIS2 is opposed to the sheet member OS in the second direction Y. Thethird surface IS3 is opposed to the sheet member OS in the thirddirection Z. In the example depicted, the first surface IS1 and thesecond surface IS2 are parallel to an X-Z plane which is defined by thefirst direction X and the third direction Z. The third surface IS3 isparallel to the X-Y plane which is defined by the first direction X andthe second direction Y, and is orthogonal to the first surface IS1 andthe second surface IS2. The first surface IS1 is opposed to the end LGe2in the second direction Y. The second surface IS2 is opposed to the endOSe in the second direction Y. The third surface IS3 corresponds to asurface connecting the first surface IS1 and the second surface IS2, andis opposed to the sheet member OS extending in the direction goingoutside the light guide plate LG in the third direction Z.

Note that a space should be provided between the end LGe2 and the firstsurface IS1, between the end OSe and the second surface IS2, and betweenthe sheet member OS and the third surface IS3 in consideration ofthermal expansion and accuracy in the process of each member.

The upper surface US is opposed to the display panel PNL in the thirddirection Z. In the example depicted, the upper surface US is opposed tothe polarizer PL1 of the display panel PNL. Note that the upper surfaceUS may be opposed to the first substrate SUB1 without the polarizer PL1interposed therebetween. The end SUB1 e of the first substrate SUB1 andthe end SUB2 e of the second substrate SUB2 are positioned just abovethe upper surface US.

In the present embodiment, at least the inner surface IS of the frame FRfunctions as a light absorbing surface which absorbs the light. Theframe FR can be formed of a material of low reflective ratio in avisible light range such as a black or gray material. Furthermore,coloring may be performed in the inner surface IS alone or in the entiresurface of the frame FR.

The adhesion member AD1 is disposed on at least the upper surface US ofthe frame FR. In the example depicted, the adhesion member AD1 adheresthe polarizer PL1 and the frame FR. Furthermore, the adhesion member AD1extends over the sheet member OS from the upper surface US and overlapsthe end OSe. In this state, the adhesion member AD1 adheres thepolarizer PL1 and the frame FR and sheet member OS. Note that, if theupper surface US is opposed to the first substrate SUB1 without thepolarizer PL1 interposed therebetween, the adhesion member AD1 mayadhere the first substrate SUB1 and the frame FR. Furthermore, theadhesion member AD1 may adhere the first substrate SUB1 and polarizerPL1 and the frame FR.

In the present embodiment, the adhesion member AD1 is light transmissiveand is a transparent double-sided tape or a transparent adhesive agent.Here, the word light transmissivity is defined that 60% or more, orpreferably 70% or more of transmissivity is achieved where thetransmissivity of the display panel PNL is given 100%. In this example,the adhesion member AD1 exerts 77% transmissivity where thetransmissivity of the display panel PNL is given 100%. Note that, if theadhesion member AD1 is a transparent double-sided tape, the double-sidedtape is, for example, a transparent polyethylene terephthalate (PET)with a transparent adhesive agent applied to both sides thereof. At thattime, a non-transparent substance may be contained therein if the abovetransmissivty is satisfied. Furthermore, the same applies to a casewhere the adhesion member AD1 is a transparent adhesive agent, that is,a non-transparent substance may be contained therein if the abovetransmissivity is satisfied.

From a different view point, it is understood that the frame FR includesa first part FR1 which is adjacent to the light guide plate LG and asecond part FR2 which is adjacent to the sheet member OS. The first partFR1 corresponds to a part on the reflective sheet RS and the second partFR2 corresponds to a part on the bottom of the display panel PNL. In thecross-section shown in the figure, the first part FR1 has a width W11 inthe second direction Y and the second part FR2 has a width W12 in thesecond direction Y. Furthermore, the width W11 is greater than the widthW12.

The upper surface US of the frame FR has the same width W12 as thesecond part FR2. Furthermore, the upper surface US overlaps with theadhesion member AD1 in the second direction Y, and the overlapping partof the upper surface US has a width W1. The adhesion member AD1 has awidth W2 in the second direction Y. The width W2 is, preferably, set tobe equal to or more than the width W1. The width W1 is half or less thanthe width W2. Furthermore, the adhesion member AD1 includes ends ADe1and ADe2. The end ADe1 is an outer end and is positioned just above theupper surface US in the example depicted. The end ADe2 is an inner endand is positioned just below the light shielding layer BM and just abovethe sheet member OS in the example depicted. Note that, in the presentembodiment, the end ADe1 corresponds to a fourth end and the end ADe2corresponds to a fifth end. Here, a gap between the end ADe2 and theboundary B is referred to as a width W3. In the present embodiment, forexample, the width W2 is approximately 0.3 to 0.8 mm, and the width W3is approximately 0.3 to 0.4 mm. Here, a sum of the width W2 and thewidth W3 is set between 0.3 and 0.8 mm, or preferably, set toapproximately 0.6 mm.

An air gap AG is formed between the sheet member OS and the displaypanel PNL. A height of the air gap AG in the third direction Z is thesame as the thickness of the adhesion member AD1 in the third directionZ. For example, even if the adhesion member AD1 does not extend over thesheet member OS, the air gap AG is, preferably, formed between the sheetmember OS and the display panel PNL to suppress deterioration in displayquality.

FIG. 6 shows a relationship between the adhesion member AD1 of thepresent embodiment and an angle θ recognized by a user U. In FIG. 6, theangle θ is defined as an angle formed by the normal N of the displaypanel PNL passing through the end BMe of the light shielding layer BMand a line L connecting the user U and the end BMe. In the exampledepicted, the angle θ is 45 degrees. At that time, on the extension ofline L, the adhesion member AD1, sheet member OS, and inner surface ISare arranged. Note that, in the present embodiment, the end BMecorresponds to a third end.

In the present embodiment, a state where the user U sees the displaydevice DSP at the angle θ (which is 45 degrees) but cannot recognizesome pixels because the light passing the pixels in the proximity of theend BMe is blocked by the adhesion member AD1 will be referred to as alack of pixels.

In the present embodiment, the display panel PNL and the frame FR areadhered by the light transmissive adhesion member AD1. In theillumination device BL, light from the light source LS propagates in thelight guide plate LG to be diffused by the sheet member OS andilluminates the display panel PNL. At that time, as shown by the line L,the light guided below the adhesion member AD1 passes through the lighttransmissive adhesion member AD1 and enters the display panel PNL. Thus,the user U can recognize the light passing the pixels in the proximityof the end BMe. That is, in the present embodiment, a lack of pixels bythe adhesion member AD1 does not occur when the user U sees the displaysurface with the angle θ of 0 to 45 degrees. Thus, deterioration indisplay quality can be suppressed.

In the present embodiment, the adhesion member AD1 is lighttransmissive, and thus, the user U can recognize the light passingthrough the pixels in the proximity of the end BMe when the user U seesthe display device DSP from the angle θ (which is 45 degrees). Notethat, at that time, the incident light reaches the frame FR, and if aconventional white resin frame is used, the incident light is reflectedby the frame and its surface periphery may be lit.

However, in the frame FR of the present embodiment, at least the innersurface IS is a light absorbing surface. Thus, even if the lightpropagating in the light guide plate LG leaks from the end LGe2 and thelight diffused in the sheet member OS leaks from the end OSe, undesiredlight reflection and diffusion in the inner surface IS of the frame FRcan be suppressed.

Therefore, the thin bezel structure can be achieved withoutdeterioration in display quality.

Furthermore, in a heating experiment or the like, even if the lightguide plate LG, sheet member OS, frame FR contract in the directiontoward the display area DA from the non-display area NDA and theadhesion member AD1 reaches the display area DA, a lack of pixels can besuppressed.

Furthermore, the sheet member OS has an end OSe opposed to the frame FRin the second direction Y. The end OSe is disposed outside the end LGe2of the light guide plate LG. Thus, the end LGe2 overlaps the sheetmember OS in the third direction Z, and the light reflected by the endLGe2 is suitably diffused by the sheet member OS when the display panelPNL is viewed from the display surface side. Furthermore, the lightreaching the end LGe2 is diffused between the sheet member OS and theframe FR by the sheet member OS. Thus, a bright line state where the endLGe2 is recognized locally bright can be suppressed.

Furthermore, the width W1 is, for example, half or less than the widthW2. Thus, the present embodiment can be applied to a thinner bezelstructure of the display device DSP.

(Variation 1)

FIG. 7 shows a variation 1 of the adhesion member AD1 of the aboveembodiment.

In the variation 1 of FIG. 7, the adhesion member AD1 is disposed on theupper surface US alone. The adhesion member AD1 is not disposed over thesheet member OS. In the example depicted, the adhesion member AD1 isdisposed on the entire surface of the upper surface US alone and thewidth W2 is the same as the width W1 of the upper surface US. In thepresent embodiment, the width W2 may be greater than the width W1, andin the example depicted, the width W2 is set to the lowermost valuewhich is, in the present embodiment, approximately 0.3 mm. The lowermostvalue is determined such that a necessary adhesion strength between thedisplay panel PNL and the frame FR can be secured.

In the structure shown in FIG. 7, a lack of pixels can be suppressedwith or without the adhesion member AD1, and thus, in achieving the thinbezel structure of the display device DSP, the accuracy in process ofthe adhesion member AD1 and a margin in the adhesion of the displaypanel PNL and the frame FR can be secured. Furthermore, in order toimprove the accuracy in process of the adhesion member AD1, materials orthe like of the adhesion member AD1 are not restricted and the costs ofthe adhesion member AD1 can be suppressed. Furthermore, decrease in theproduction caused by misalignment of the adhesion member AD1 can besuppressed. Furthermore, since there is no need of expensive facilitiesto improve the alignment of the adhesion member AD1, the costs can besuppressed further.

(Variation 2)

FIG. 8 shows a variation 2 of the adhesion member AD1 of the aboveembodiment.

As compared to the variation 1 of FIG. 7, in the variation 2 of FIG. 8,the adhesion member AD1 has a greater width W2. The adhesion member AD1extends from the upper surface US of the frame FR over the sheet memberOS. The end ADe1 of the adhesion member AD1 is disposed in a positionoverlapping the end BMe of the light shielding layer BM. In the exampledepicted, the width W3 is zero and the width W2 is set to the uppermostvalue which is, in the present embodiment, approximately 0.8 mm. Theuppermost value is determined such that visual discrepancy betweenpixels in the display area DA caused by the adhesion member AD1extending over the display area DA (visual discrepancy between thepixels which do not overlap the adhesion member AD1 in the center of thedisplay area and the pixels which overlap the adhesion member AD1 in theperiphery of the display area DA) is not caused.

The width W2 is set to, preferably, a value between the lowermost valueof FIG. 7 and the uppermost value of FIG. 8.

(Variation 3)

FIG. 9 is a perspective view showing a variation 3 of the display deviceof the above embodiment. As compared to the example shown in FIG. 1, inthe variation 3, the display device DSP includes a case C instead of theframe. The case C functions as a container in which the reflective sheetRS, light guide plate LG, optical sheet OS, and light unit LU areaccommodated. The detailed structure of the case C will be explainedwith reference to FIG. 10.

FIG. 10 is a cross-sectional view of the display device of FIG. 9. Thecase C includes a frame FR and a bezel BZ. The frame FR corresponds tothe frame of FIG. 1 and its detailed structure will be omitted. Thebezel BZ is formed of a metal; however, it may be formed of a differentmaterial such as a resin. In the display area DA, the reflective sheetRS, light guide plate LG, and optical sheet OS are laminated on thebezel BZ in this order in the third direction Z. The case C includes theupper surface US. The upper surface US includes an upper surface US1 ofthe frame FR and an upper surface US2 of the bezel BZ. The uppersurfaces US1 and US2 are parallel to the X-Y plane, and in the exampledepicted, the upper surface US1 and the upper surface US2 form the sameflat surface. The adhesion member AD1 is disposed on the polarizer PL1and between the upper surfaces US1 and US2. In the example depicted, theadhesion member AD1 is disposed between the polarizer PL1 and the sheetmember OS.

In the variation 3, at least the inner surface IS of the frame FR is alight absorbing surface, and the adhesion member AD1 is lighttransmissive. Therefore, the same advantages described above can beachieved.

As can be understood from the above, the present embodiment can achievean illumination device and a liquid crystal display device by whichdeterioration in the display quality can be suppressed.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

Examples of an illumination device and a liquid crystal display deviceachieved from the structures disclosed in the present application willbe listed below.

(1) An illumination device comprising:

a light source disposed along a first direction;

a light guide plate including a first end and a second end, the secondend being positioned to be opposite to the first end in a seconddirection which crosses the first direction;

a frame disposed along the second end and including an inner surface andan upper surface; and

an adhesion member disposed on at least the upper surface of the frame,wherein

the light source is disposed at the first end along the first direction,

at least the inner surface of the frame is a light absorbing surface,and

the adhesion member is light transmissive.

(2) The illumination device according to (1), wherein the frame isblack.

(3) The illumination device according to (1), wherein the adhesionmember is a transparent double-sided tape or a transparent adhesiveagent.

(4) The illumination device according to (1), further comprising a sheetmember disposed on the light guide plate, wherein

the frame includes a first part adjacent to the light guide plate in thesecond direction, and, a second part adjacent to the sheet member in thesecond direction, and

a width of the first part in the second direction is greater than awidth of the second part in the second direction.

(5) The illumination device according to (4), wherein

the inner surface includes a first surface, a second surface, and athird surface, and

the first surface is opposed to the light guide plate in the seconddirection,

the second surface is opposed to the sheet member in the seconddirection, and

the third surface is opposed to the sheet member in a third directionwhich crosses the first direction and the second direction.

(6) The illumination device according to (1), wherein a width of theadhesion member in the second direction is equal to or more than a widthof the upper surface in the second direction.

(7) The illumination device according to (1), wherein

the upper surface overlaps with the adhesion member in the seconddirection, a width of the overlapping part of the upper surface is halfor less than a width of the adhesion member in the second direction.

(8) The illumination device according to (4), wherein the adhesionmember extends over the sheet member from the upper surface.

(9) A liquid crystal display device comprising:

a display panel including:

a first substrate,

a second substrate opposed to the first substrate,

a liquid crystal layer held between the first substrate and the secondsubstrate, and

a polarizer adhered to the first substrate; and

an illumination device which illuminates the display panel, wherein

the illumination device comprises:

a light source disposed along a first direction;

a light guide plate including a first end and a second end, the secondend being positioned to be opposite to the first end in a seconddirection which crosses the first direction;

a frame disposed along the second end and including an inner surface andan upper surface; and

an adhesion member disposed between the display panel and the frame andadheres the display panel and the frame, wherein

the light source is disposed at the first end along the first direction,

at least the inner surface of the frame is a light absorbing surface,and

the adhesion member is light transmissive.

(10) The liquid crystal display device according to (9), wherein theadhesion member adheres the polarizer and the frame.

(11) The liquid crystal display device according to (9), furthercomprising a sheet member disposed on the light guide plate, wherein theadhesion member adheres the polarizer and the frame, and the polarizerand the sheet member.

(12) The liquid crystal display device according to (9), wherein theframe is black.

(13) The liquid crystal display device according to (9), wherein theadhesion member is a transparent double-sided tape or a transparentadhesive agent.

(14) The liquid crystal display device according to (9), furthercomprising a sheet member disposed on the light guide plate, wherein

the frame includes a first part adjacent to the light guide plate in thesecond direction and a second part adjacent to the sheet member in thesecond direction, and

a width of the first part in the second direction is greater than awidth of the second part in the second direction.

(15) The liquid crystal display device according to (11), wherein theinner surface includes a first surface, a second surface, and a thirdsurface, and

the first surface is opposed to the light guide plate in the seconddirection,

the second surface is opposed to the sheet member in the seconddirection, and

the third surface is opposed to the sheet member in a third directionwhich crosses the first direction and the second direction.

(16) The liquid crystal display device according to (9), wherein a widthof the adhesion member in the second direction is equal to or more thana width of the upper surface in the second direction.

(17) The liquid crystal display device according to (9), wherein

the upper surface overlaps with the adhesion member in the seconddirection,

a width of the overlapping part of the upper surface is half or lessthan a width of the adhesion member in the second direction.

(18) The liquid crystal display device according to (9), wherein thedisplay panel includes a light shielding layer disposed in a non-displayarea surrounding a display area, and

the light shielding layer includes a third end disposed in a boundary ofthe display area and the non-display area, and

the adhesion member includes

a fourth end disposed above the upper surface, and

a fifth end disposed in a side closer to the third end than to thefourth end and below the light shielding layer.

(19) A liquid crystal display device comprising:

a display panel including:

a first substrate,

a second substrate opposed to the first substrate,

a liquid crystal layer held between the first substrate and the secondsubstrate, and

a light shielding layer disposed in a non-display area around a displayarea; and

an illumination device which illuminates the display panel, wherein

the illumination device comprises:

a light source disposed along a first direction;

a light guide plate including a first end and a second end, the secondend being positioned to be opposite to the first end in a seconddirection which crosses the first direction;

a frame disposed along the second end; and

an adhesion member disposed between the display panel and the frame andadheres the display panel and the frame, wherein

the light source is disposed at the first end along the first direction,

the light shielding layer includes an end positioned in a boundarybetween the display area and the non-display area, and

a light shielding member is not disposed, in a plane defined by thesecond direction and a third direction which crosses the first directionand the second direction, on a line passing the end of the lightshielding layer and the frame, wherein the line is at an angle of 45degrees with respect to the normal of the display panel.

(20) The liquid crystal display device according to (19), wherein theframe is black and the adhesion member is transparent.

What is claimed is:
 1. A liquid crystal display device comprising: adisplay panel including: a first substrate, a second substrate opposedto the first substrate, a liquid crystal layer held between the firstsubstrate and the second substrate, a polarizer adhered to the firstsubstrate; and an illumination device which illuminates the displaypanel, wherein the illumination device comprises: a light unit includinglight sources arranged in a first direction; a light guide plateincluding a first end and a second end, the second end being positionedto be opposite to the first end in a second direction which crosses thefirst direction; a sheet member disposed between the light guide plateand the polarizer; a frame disposed along at least the second end andincluding an inner surface and an upper surface; and an adhesion memberdisposed on the upper surface of the frame, the adhesion member extendsover the sheet member from the upper surface of the frame and overlapsan end portion of the sheet member such that the adhesion member adheresthe polarizer and the frame, and also adheres the polarizer and thesheet member, the light guide plate, the sheet member and the displaypanel are stacked in a third direction which crosses the first directionand the second direction, and the frame is adjacent to the light guideplate in the second direction.
 2. The liquid crystal display deviceaccording to claim 1, wherein the adhesion member adheres the polarizerand the frame, and the adhesion member is in contact with a lowersurface of the polarizer and the upper surface of the frame.
 3. Theliquid crystal display device according to claim 1, wherein the frame isblack.
 4. The liquid crystal display device according to claim 1,wherein the adhesion member is a transparent double-sided tape or atransparent adhesive agent.
 5. The liquid crystal display deviceaccording to claim 1, wherein the frame includes a first part adjacentto the light guide plate in the second direction and a second partadjacent to the sheet member in the second direction, and a width of thefirst part in the second direction is greater than a width of the secondpart in the second direction.
 6. The liquid crystal display deviceaccording to claim 1, wherein the inner surface includes a firstsurface, a second surface, and a third surface, the first surface isopposed to the light guide plate in the second direction, the secondsurface is opposed to the sheet member in the second direction, thethird surface is opposed to the sheet member in the third direction, andan end of the adhesion member overlaps the second surface.
 7. The liquidcrystal display device according to claim 1, wherein a width of theadhesion member in the second direction is equal to or more than a widthof the upper surface in the second direction.
 8. The liquid crystaldisplay device according to claim 1, wherein the upper surface overlapsthe adhesion member in the second direction, and a width of theoverlapping part of the upper surface is half or less than a width ofthe adhesion member in the second direction.
 9. The liquid crystaldisplay device according to claim 1, wherein the display panel includesa light shielding layer disposed in a non-display area surrounding adisplay area, the light shielding layer includes a third end disposed ina boundary of the display area and the non-display area, and theadhesion member includes a fourth end disposed above the upper surface,and a fifth end disposed in a side closer to the third end than to thefourth end and below the light shielding layer.